Method of treating leather



Patented Sept. 2, 1930 UNITED STATES PATENT OFFICE WILLIAM H. ALLEN. OFDETROIT. MICHIGAN; DOROTHEA ALLEN. EXECUTRIX OF SAID WILLIAM H. ALLEN,DECEASED. ASSIGNOR TO GEORGE EDWIN MAURER, OF PHILA- DELPHIA,PENNSYLVANIA METHOD OF TREATING LEATHER No Drawing.

The present invention relates to a method of treating leather and to theproduct produced thereby.

Heretofore in the production of leather from the skins of certainanimals. the products are limited in their application. and. thereforetheir value. by reason of the fact that they are soft and spongy and oflittle strengthand resistance to wear and distortion.

Among the objects of the present invention is to overcome suchobjections and to prodiu-e a leather t'rom these same kinds of .skinswhich has much greater body, is

to dialyse into the membranes.

tough and strong and is capable of being used satisfactorily forpurposes for which it was not before adapted.

The process consists in what might be called a tlensifying process. asexamination of the product indicates an apparent lessening of theintercellular spaces and a thickening of the cell walls with a verygreat increase in tensile strength. and involves a treatment preferablyintermediate the tanning and finishing steps.

In carrying out the process. the preferred method comprises placing thestill wet skin from the tanning process. in a solution of a deliquescentsalt that has no chemical affinity for the tanned skin. leaving the skinin said solution sufiiciently long for the salt After a sufficient timehas elapsed usually from one to one and one half hours. the skin is byany suitable method. such as rolling then taken from the solution. theexcess water removed. and allowed to drv.

Application filed August 5. 1927.

In the drying. the skin shrinks uniformlv.

Serial No. 211,003.

finished. While the preferred method involves the soaking of the skin inthe solution of the treating salt. this step may also be carried out bysprinkling a solution of the salt upon the skin or the dry saltsprinkled thereon and folded or rolled up in the wet skin.

The preferred treatment is with a 10 to 30% solution of calcium chloridebut magnesium chloride may be substituted with good results.

In those cases where the color produced will not be objectionable ferricchloride may also be used to produce the desired densitying.

The action seems to be due to an abstraction of the last traces ofuncombined water from the hide substance.

Further. either bark tanned or chrome tanned skins may be treated in theprocess and these may be either with or Without the naturally attachedhair on them as the treatmentdoes not in any way atfect the hair exceptto thicken the fur by the reduction in area of the skin. Also while, thetreatment may be applied to any kind of tanned skins. itis mostbeneficial for such skins as sheepskins or any that ordinarily are soft,spongy and of little strength.

The softer parts of cowhides such as the belly and sides may be lessenedin areaand increased in thickness and ,in tensile strength by saidprocess and thus made suitable for applications where heretofore onlyselected portions have been considered fit.

Now having described the invention and the preferred forms of embodimentthereof, it is to be understood that the said invention is to be limitednot to the specific details herein set forth but only by the scope ofthe claims which follow.

I claim 1. The process of treating tanned skins of animals whichcomprises in'ipregnating said skins with a salt inert to the tanned hidesubstance and capable of absorbing water, drying the impregnated skinand halt-- ing the shrinkage thereby produced at the desired point byWashing out the salt, and subsequently finishing the product.

2. The process of treating tanned skins of animals which comprisesimpregnating said skins with calcium chloride, drying the impregnatedskin and halting the shrinkage thereby produced at the desired point bywashing out the salt, and subsequently finishing the product.

3. The process of treating tanned skins of animals which comprisessoaking the wet skins from the tanning process in a solution of calciumchloride until thoroughly impregnated, drying said skins and therebycausing shrinkage, stopping said shrinkage at the desired point bywashing out the calcium chloride, and subsequently finishing the sotreated leather.

' WILLIAM H. ALLEN.

